Degradation thermoplastics

Wehrenberg, R. J., Lactic acid polymers Strong degradable thermoplastics, Mater. Eng., 3, 163, 1981. 

The best way for the reader to learn is to study actual examples of parts made by the blow molding of fluoropolymers. A majority of such parts have a multilayer construction to combine the properties of other plastics in a composite structure. The most common technique for producing multilayer sheet/film is coextrusion. The chemical resistance of fluoropolymers makes them attractive materials for inner layers of containers that come in contact with aggressive chemicals that can swell or degrade thermoplastics. 

Application Scope applicable for non-oxidizing and non-degradable thermoplastic or inorganic polymer materials near the softening point or melting point. 

Degradative Thermoplastic Oil-like/wax-like, Polymer chain degradation in... 

A remarkable characteristic of PHAs is their biodegradability in various environments. The PHA-degrading microorganisms were first isolated by Chowdhury in 1963. Subsequently, however, only a few studies on isolation and characterization of PHA-degrading microorganisms were reported for three decades. With the increased demand to use microbial PHA polymers as environmentally degradable thermoplastic, the... 

Bruns, M.C. and O.A. Ezekoye (2014) Modeling differential scanning calorimetry of thermally degrading thermoplastics. J Anal Appl Pyrol 105, 241-251. 

These biodegradable PHA polymers have attracted attention as environmentally degradable thermoplastics to be used for a wide range of agricultural, marine, and medical applications. This paper surveys the biosynthesis and properties of bacterial PHA. 

The materials that degrade into small stable particles are blends often starches are blended with non-degradable thermoplastics such as PE. The same considerations noted in this section on multiphase polymers hold true for these blends. For instance, the interfacial energy and rheology play a role in the size of the dispersed phases. These blends can often be processed by standard melt forming polymer techniques, by compounding and extrusion into films and fibers and injection or blow molded to form polymer... 

Degradable thermoplastic elastomers having shape memory properties... 

Despite their undesirable durability after disposal, plastics are hard to replace because of their low cost and versatility. Plasticwares are inexpensive mainly because they can be mass-produced from historically inexpensive raw materials. The thermoplastics have allowed the use of machines and procedures to mass-produce a very wide range of consumer products. It is thus obvious that if a low-cost, environmentally degradable thermoplastic is available, the new material will allow the continued production of inexpensive but nonpolluting plasticwares for the future generations. This need is the driving force for active research on PHAs. 

Thermoplastic based binders are by far the most widely used. These forms of binder usually contain a wax as a major component and a thermoplastic as the minor component. Additives are usually added for lubrication, viscosity control, wetting and improving powder-binder interaction. Debinding of such binders is normally achieved via thermal degradation, wicking, solvent extraction or even photo-degradation. Thermoplastics commonly used include polyethylene, polystyrene, polypropylene and ethylene vinyl acetate. Table 2 highlights some of the common thermoplastics used in PIM or MIM processes. 

Wehrenberg, R.H. (1981) Polylactic acid polymers strong, degradable thermoplastics. Mater. Eng. 94, 63-66. 

Wood or plant fibres are of interest in polymer reinforcement for a number of reasons, espeeially their low cost, low weight and non-abrasiveness to proeessing equipment. In addition, natural fibres are C02-neutral when burned, have attractive aeoustic and thermal insulation properties and have good specific mechanical properties. The research literature contains many examples of studies in whieh the reinforcement of non-degradable thermoplastics like polypropylene (PP), polyethylene (PE), polyvinyl ehloride (PVC) and polyesters with wood or plant fibres has been investigated (Bledzki and Gassan, 1999 Kandaehar, 2002). Reinforcement of thermosets such as epoxies and polyurethanes with natural fibres has also been explored. A summary of the mechanieal properties of selected plant fibres derived from various literature sourees is shown in Table 8.1 (Lilholt and Lawther, 2000 Kandaehar, 2002 Bledzki and Gassan, 1999 Wambua et al, 2003). 

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